Machines, such as grinders and chippers, are used both commercially and non-commercially for shredding, grinding, and/or chipping a variety of materials. Grinders, for example, typically include a grinding chamber having a grinding drum, and a conveying system that transports the various materials to the grinding chamber. Many conventional grinders have an anvil positioned adjacent to the conveying system at a location just prior to where the material enters the grinding chamber. The anvil provides a solid surface that accommodates impact forces, produced by tips or hammers of the grinding drum, and transferred through the material being ground.
In use, material is fed into the grinding chamber of conventional machines at a feed rate generally dictated by the speed of the conveying system. The speed of the conveying system is set to correspond to the machine's grinding capacity. In some circumstances, the rotational motion of the grinding drum and the hammers can cause the hammers or tips to grip and pull the conveyed material into the grinding chamber at a rate that exceeds the machine's grinding capacity. When the incoming material is pulled into the grinding chamber at too great a rate, the machine can plug, reducing the grinding efficiency of the machine, and even causing the machine to stall.
The conveying system of some conventional grinders includes a lower feed conveyor and an upper roller. The upper roller, in cooperation with the lower feed conveyor, functions to transport the material to the grinding chamber. The upper roller is often partly enclosed by a shroud or shoot having sidewalls. On some occasions, material is forced between the roller and the shroud sidewalls, and collects within a volume located at the open ends of the roller. The material becomes trapped within open ends of the roller due to the proximity of the roller ends to shroud sidewalls. As material collects within the open ends of the roller, the increasing volume of material within the roller begins to drag or scrape against the sidewalls, and can sometimes jam between the roller and the sidewall. The collected, trapped material creates an undesirable drag on the conveying system, and can even subsequently stall the conveying system.
The region adjacent to the conveying system and just prior to where the material enters the grinding chamber is often referred to as a transition region. In some conventional arrangements, the transition region includes a transition plate located adjacent to the lower feed conveyor. A gap or opening exists between the transition plate and the lower feed conveyor of conventional machines. During operation, chips and other small pieces of material often fall through the opening. The pile of material that builds up underneath the machine requires a user to expend extra time and effort in clean up and maintenance of a work site.
In general, improvement has been sought with respect to such conventional grinder machines, generally to address the problems previously described.